In order to better understand these problems, could you please tell us if the cited design has been developed by you or a third party company? In case that it is a third party design, please give us all the information related to this implementation.

Also, could you please try to replicate these problems using any of the following Operating System (OS)?

We use Win7 Embedded Standard and Windows 10 IoT 2016 LTSB to run this board.

On both operating system we use CeWin which is a realtime extention for Windows 7/10. (It's WinCE 6.0)

The system running Win7 actually we have no problems. Only on the Win10 systems.

What we already found out:

a) the black screen only comes up after restarting windows (warm start). It never appears after a power up.

b) In case of a black screen after reboot, the windows try to run 1024x768 px on the 800x600 TFT display.

c) I have made a "snapshot" image (acronis true image) of a situation where nearly 99% of the restart's the screen is black. But when I restore this image directly, it hapens only 1% or 2% ???? So something has been changed by the backup and restore procedure.

d) When I delete the boot parameter FIRSTMEGABYTEPOLICY everything is fine. (except the situation that our real time system is not working :-) )

My suggestion:

Something happend during the shutdown proccess. Maybe the diplay driver didn't do a proper deinit.Or the worst case is that the E3845 has a bug that a memory access is mistaken a port I/O access and the dynamicallocated memory the sometimes the same address a the display interface.

I want to do a small test but I don't know how to do it :-(

What happens if I can lock a defined area of pysical memory which has the same adress as the display interface.

When I look at the output of "RamMap" I see that some memory is used by "Driver Locked". How can I do this manualy ?

I try to write a device driver (I have done this for NT4.0 twenty years ago) but the function MmAllocateContiguousMemory() does notspecify a exact memory range.

Due to this fact, we suggest you use Operating Systems listed as supported to avoid these inconveniences. Please keep in mind that this information should be confirmed by the manufacturer of the affected board, which must give you the accurate information and solutions to their implementations.